<?php

/**
 * @package php-font-lib
 * @link    http://php-font-lib.googlecode.com/
 * @author  Fabien M�nager <fabien.menager@gmail.com>
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @version $Id: font_binary_stream.cls.php 42 2012-02-05 10:49:20Z fabien.menager $
 */

/**
 * Generic font file binary stream.
 * 
 * @package php-font-lib
 */
class Font_Binary_Stream {

    /**
     * @var resource The file pointer
     */
    protected $f;

    const uint8 = 1;
    const int8 = 2;
    const uint16 = 3;
    const int16 = 4;
    const uint32 = 5;
    const int32 = 6;
    const shortFrac = 7;
    const Fixed = 8;
    const FWord = 9;
    const uFWord = 10;
    const F2Dot14 = 11;
    const longDateTime = 12;
    const char = 13;

    private static $sizes = array(
        self::uint8 => 1,
        self::int8 => 1,
        self::uint16 => 2,
        self::int16 => 2,
        self::uint32 => 4,
        self::int32 => 4,
        self::shortFrac => 4,
        self::Fixed => 4,
        self::FWord => 2,
        self::uFWord => 2,
        self::F2Dot14 => 2,
        self::longDateTime => 8,
        self::char => 1,
    );

    const modeRead = "rb";
    const modeWrite = "wb";
    const modeReadWrite = "rb+";

    /**
     * Open a font file in read mode
     * 
     * @param string $filename The file name of the font to open
     */
    public function load($filename) {
        return $this->open($filename, self::modeRead);
    }

    /**
     * Open a font file in a chosen mode
     * 
     * @param string $filename The file name of the font to open
     * @param string $mode The opening mode 
     */
    public function open($filename, $mode = self::modeRead) {
        if (!in_array($mode, array(self::modeRead, self::modeWrite, self::modeReadWrite))) {
            throw new Exception("Unkown file open mode");
        }

        $this->f = fopen($filename, $mode);
        return $this->f != false;
    }

    /**
     * Close the internal file pointer
     */
    public function close() {
        return fclose($this->f) != false;
    }

    /**
     * Change the internal file pointer
     * 
     * @param resource $fp
     */
    public function setFile($fp) {
        if (!is_resource($fp)) {
            throw new Exception('$fp is not a valid resource');
        }

        $this->f = $fp;
    }

    /**
     * Create a temporary file in write mode
     * 
     * @return resource the temporary file pointer resource
     */
    public static function getTempFile($allow_memory = true) {
        $f = null;

        if ($allow_memory) {
            // PHP 5.1+
            @fopen("php://temp", "rb+");
        }

        if (!$f) {
            $f = fopen(tempnam(sys_get_temp_dir(), "fnt"), "rb+");
        }

        return $f;
    }

    /**
     * Move the internal file pinter to $offset bytes
     * 
     * @param int $offset
     * @return bool True if the $offset position exists in the file
     */
    public function seek($offset) {
        return fseek($this->f, $offset, SEEK_SET) == 0;
    }

    /**
     * Gives the current position in the file
     * 
     * @return int The current position
     */
    public function pos() {
        return ftell($this->f);
    }

    public function skip($n) {
        fseek($this->f, $n, SEEK_CUR);
    }

    public function read($n) {
        if ($n < 1)
            return "";
        return fread($this->f, $n);
    }

    public function write($data, $length = null) {
        if ($data === null || $data === "")
            return;
        return fwrite($this->f, $data, $length);
    }

    public function readUInt8() {
        return ord($this->read(1));
    }

    public function writeUInt8($data) {
        return $this->write(chr($data), 1);
    }

    public function readInt8() {
        $v = $this->readUInt8();

        if ($v >= 0x80) {
            $v -= 0x100;
        }

        return $v;
    }

    public function writeInt8($data) {
        if ($data < 0) {
            $data += 0x100;
        }

        return $this->writeUInt8($data);
    }

    public function readUInt16() {
        $a = unpack("nn", $this->read(2));
        //if ($a == null) var_dump(debug_backtrace(false));
        return $a["n"];
    }

    public function writeUInt16($data) {
        return $this->write(pack("n", $data), 2);
    }

    public function readInt16() {
        $v = $this->readUInt16();

        if ($v >= 0x8000) {
            $v -= 0x10000;
        }

        return $v;
    }

    public function writeInt16($data) {
        if ($data < 0) {
            $data += 0x10000;
        }

        return $this->writeUInt16($data);
    }

    public function readUInt32() {
        $a = unpack("NN", $this->read(4));
        return $a["N"];
    }

    public function writeUInt32($data) {
        return $this->write(pack("N", $data), 4);
    }

    public function readFixed() {
        $d = $this->readInt16();
        $d2 = $this->readUInt16();
        return round($d + $d2 / 0x10000, 4);
    }

    public function writeFixed($data) {
        $left = floor($data);
        $right = ($data - $left) * 0x10000;
        return $this->writeInt16($left) + $this->writeUInt16($right);
    }

    public function readLongDateTime() {
        $this->readUInt32(); // ignored 
        $date = $this->readUInt32() - 2082844800;

        return strftime("%Y-%m-%d %H:%M:%S", $date);
    }

    public function writeLongDateTime($data) {
        $date = strtotime($data);
        $date += 2082844800;

        return $this->writeUInt32(0) + $this->writeUInt32($date);
    }

    public function unpack($def) {
        $d = array();
        foreach ($def as $name => $type) {
            $d[$name] = $this->r($type);
        }
        return $d;
    }

    public function pack($def, $data) {
        $bytes = 0;
        foreach ($def as $name => $type) {
            $bytes += $this->w($type, $data[$name]);
        }
        return $bytes;
    }

    /**
     * Read a data of type $type in the file from the current position
     * 
     * @param mixed $type The data type to read
     * @return mixed The data that was read
     */
    public function r($type) {
        switch ($type) {
            case self::uint8: return $this->readUInt8();
            case self::int8: return $this->readInt8();
            case self::uint16: return $this->readUInt16();
            case self::int16: return $this->readInt16();
            case self::uint32: return $this->readUInt32();
            case self::int32: return $this->readUInt32();
            case self::shortFrac: return $this->readFixed();
            case self::Fixed: return $this->readFixed();
            case self::FWord: return $this->readInt16();
            case self::uFWord: return $this->readUInt16();
            case self::F2Dot14: return $this->readInt16();
            case self::longDateTime: return $this->readLongDateTime();
            case self::char: return $this->read(1);
            default:
                if (is_array($type)) {
                    if ($type[0] == self::char) {
                        return $this->read($type[1]);
                    }

                    $ret = array();
                    for ($i = 0; $i < $type[1]; $i++) {
                        $ret[] = $this->r($type[0]);
                    }
                    return $ret;
                }
        }
    }

    /**
     * Write $data of type $type in the file from the current position
     * 
     * @param mixed $type The data type to write
     * @param mixed $data The data to write
     * @return int The number of bytes read
     */
    public function w($type, $data) {
        switch ($type) {
            case self::uint8: return $this->writeUInt8($data);
            case self::int8: return $this->writeInt8($data);
            case self::uint16: return $this->writeUInt16($data);
            case self::int16: return $this->writeInt16($data);
            case self::uint32: return $this->writeUInt32($data);
            case self::int32: return $this->writeUInt32($data);
            case self::shortFrac: return $this->writeFixed($data);
            case self::Fixed: return $this->writeFixed($data);
            case self::FWord: return $this->writeInt16($data);
            case self::uFWord: return $this->writeUInt16($data);
            case self::F2Dot14: return $this->writeInt16($data);
            case self::longDateTime: return $this->writeLongDateTime($data);
            case self::char: return $this->write($data, 1);
            default:
                if (is_array($type)) {
                    if ($type[0] == self::char) {
                        return $this->write($data, $type[1]);
                    }

                    $ret = 0;
                    for ($i = 0; $i < $type[1]; $i++) {
                        $ret += $this->w($type[0], $data[$i]);
                    }
                    return $ret;
                }
        }
    }

    /**
     * Converts a Uint32 value to string
     * 
     * @param int $uint32
     * @param string The string
     */
    public function convertUInt32ToStr($uint32) {
        return chr(($uint32 >> 24) & 0xFF) . chr(($uint32 >> 16) & 0xFF) . chr(($uint32 >> 8) & 0xFF) . chr($uint32 & 0xFF);
    }

}
